The present invention relates to the aircraft alerting and display system arts and, in particular, to a method and apparatus for realizing a dynamic, multi-attribute aircraft hazard prioritization system.
As used herein, the term "hazard" refers to any element of an aircraft's environment which could possibly constitute a threat to that aircraft, its occupants, or its intended mission; and the term "alert" refers to any indication of that hazard which is presented to the flight crew, whether by visual, aural, or other means.
In modern commercial aircraft, there are many warning systems, each providing the flight crew with information about one or more of the hazards to which the aircraft is exposed. These systems typically include a terrain alerting system (such as the ground proximity warning system), predictive and reactive windshear systems, and a traffic alert and collision avoidance system. Such systems produce alerts which may be presented to the flight crew visually or through audible tones or voices. Since many of the audio and visual displays used to present these alerts can only present one alert at a time, while the hazards which give rise to the alerts can occur simultaneously, it is necessary to prioritize the hazards so that the more important alert is presented.
In previous systems, this has been achieved by using a static prioritization scheme in which the hazards are arranged in order of priority--as determined when the warning or display systems are designed or integrated into the aircraft. The prioritization scheme, which may be implemented through the use of discrete signals between the warning systems or through the use of a prioritization list implemented in one of the warning systems, is then fixed. When two or more alerts are generated simultaneously, the alert for the hazard with the highest priority is presented to the flight crew.
There are two main drawbacks to the prior art method of prioritization. First, because the priorities are predetermined, information from the alerting system, such as the distance in time to the situation which has triggered the alert, cannot be used at the time the alerts are generated. For example, if two warning systems, A and B generate alerts for hazards which are 30 to 60 seconds away and 15 to 45 seconds away respectively, a static prioritization scheme would be designed to give priority to system B, since it typically generates alerts for hazards which are closer. However, this would be inappropriate for the case in which system B happened to generate an alert for a hazard which was 45 seconds away while system A was generating an alert for a hazard which was only 30 seconds away.
The second drawback of the prior art method of prioritization is that each hazard has several relevant features--or attributes--which must be considered during prioritization. These other attributes also have a variable element which cannot be accounted for at the design stage. Among these are:
The potential severity of the hazard (for example, terrain is usually considered to be a more significant threat than traffic, and should therefore be given higher priority),
The distance and time to the hazard (closer hazards should be given higher priority), and
The time required for the response to the hazard (if a hazard requires a longer response then it should be given higher priority, all other things being equal).
These and other attributes must all be considered in prioritizing hazards, but there is currently no accepted method of, or apparatus for realizing such consideration.